Torque index sensor and steering device comprising same

ABSTRACT

A torque index sensor may be provided which comprises: a substrate; a first cover which accommodates the circuit board; a first hall sensor and a second hall sensor which are disposed on the circuit board; a magnet seating member which is coupled to the stator; a second magnet which is coupled to the magnet seating member; and a second cover made of a metal material coupled with the first cover, wherein the magnet seating member and the second magnet are disposed between the first cover and the second cover, wherein the second cover comprises: an upper plate on which a through hole is formed; and a side plate which extends in the rotational axis direction from the upper plate, and wherein the side plate comprises a groove formed at a position corresponding to the hall sensor.

CROSS REFERENCE TO RELATED APPLICATIONS

This application is the National Phase of PCT International ApplicationNo. PCT/KR2017/012572, filed on Nov. 8, 2017, which claims priorityunder 35 U.S.C. 119(a) to Patent Application No. 10-2016-0148097, filedin the Republic of Korea on Nov. 8, 2016 and Patent Application No.10-2016-0161711, filed in the Republic of Korea on Nov. 30, 2016, all ofwhich are hereby expressly incorporated by reference into the presentapplication.

TECHNICAL FIELD

An embodiment relates to a torque index sensor and a steering deviceincluding the same.

BACKGROUND ART

Since a power steering system (hereinafter, referred to as an electronicpower system (EPS)) drives a motor in an electronic control unitaccording to a driving condition to ensure cornering stability andprovide a quick restoring force, a driver can drive safely.

The EPS includes a torque index sensor configured to measure torque, asteering angle, and the like of a steering shaft to provide appropriatetorque. The torque index sensor can be provided with a torque sensorconfigured to measure torque loaded to the steering shaft and an indexsensor configured to measure angle acceleration of the steering shaft.The steering shaft can include an input shaft connected to a handle, anoutput shaft connected to a power transmission structure of the wheelside, and a torsion bar configured to connect the input shaft and theoutput shaft.

The torque sensor measures a torsion degree of the torsion bar tomeasure the torque loaded to the steering shaft. Further, the indexsensor senses rotation of the output shaft to measure the angleacceleration of the steering shaft. In the torque index sensor, thetorque sensor and the index sensor may be disposed together to beintegrally configured.

However, in the torque index sensor, magnetic field interference occursbetween the torque sensor and the index sensor. Accordingly, in order toprevent the magnetic field interference, a magnetic field shieldingstructure is separately provided between the torque sensor and the indexsensor. Accordingly, when an overall thickness of the torque indexsensor is decreased, a magnetic field shielding plate and a magnetbecome close to each other and thus a magnetic leakage occurs. Further,there is a limit in reducing the overall thickness of the torque indexsensor due to an installation space of the magnetic field shieldingstructure. As a result, there is a problem that the magnetic fieldshielding structure becomes an important factor for increasing theoverall thickness of the torque index sensor.

DISCLOSURE Technical Problem

The present invention is directed to providing a torque index sensorcapable of preventing magnetic field interference and reducing athickness thereof and a steering device including the same.

Problems desired to be solved by the present invention are not limitedto the above-described problems, and purposes and effects understoodfrom solutions and embodiments which will be described below are alsoincluded.

Technical Solution

One aspect of the present invention provides a torque index sensorincluding a rotor having an outer circumferential surface on which afirst magnet is disposed, a stator disposed at the outside of the rotor,a circuit board, a first cover configured to accommodate the circuitboard, a first Hall sensor and a second Hall sensor mounted on thecircuit board, a magnet seating member coupled to the stator, a secondmagnet coupled to the magnet seating member, and a second cover made ofa metal material and coupled to the first cover, wherein the magnetseating member and the second magnet are disposed between the firstcover and the second cover, the second cover includes an upper plate inwhich a through hole is formed and a side plate configured to extend ina rotational axis direction from the upper plate, and the side plateincludes a groove formed at a location corresponding to the second Hallsensor.

The first Hall sensor may sense magnetic flux of the stator, and thesecond Hall sensor may sense magnetic flux of the second magnet.

The first cover may include a 1-1 cover and a 1-2 cover, the 1-1 covermay include a first hole through which the rotor passes, the 1-2 covermay include a second hole through which the stator passes, and thecircuit board may be disposed between the 1-1 cover and the 1-2 cover.

The substrate includes a first surface facing the 1-1 cover and a secondsurface facing the 1-2 cover, the first Hall sensor may be disposed onthe first surface, and the second Hall sensor may be disposed on thesecond surface.

The side plate may be disposed between the second magnet and the secondHall sensor on the basis of a direction perpendicular to an axialdirection of the rotational axis.

The first cover may include a Hall sensor housing configured to protrudefrom an outer surface of the first cover and in which the second Hallsensor is located. The Hall sensor housing may be provided with a slotconfigured to accommodate the second Hall sensor, and the slot may havean open surface.

The slot may include a stopper configured to protrude from an inlet ofthe open surface.

The first cover may include an accommodation part disposed on an outersurface thereof and concavely disposed along a circumference of thefirst hole through which the stator passes so that the magnet seatingmember is seated.

The magnet seating member may include a first surface facing the secondcover and a second surface facing the first cover, and the second magnetmay be disposed on the first surface.

The magnet seating member may include a first coupling part coupled tothe stator in the direction perpendicular to the axial direction of therotational axis.

The stator may include two stator rings and a molding member configuredto fix the two stator rings, and the molding member may include a secondcoupling part coupled to the first coupling part.

The first coupling part may be at least one protrusion configured toprotrude from an inner circumferential surface of the magnet seatingmember, and the second coupling part may be a groove disposed in anouter circumferential surface of the stator holder and into which thefirst coupling part is inserted.

The first cover may include a Hall sensor housing configured to protrudefrom an outer surface of the first cover and in which the second Hallsensor is located, and the groove of the side plate of the second coverand the Hall sensor housing may be aligned on the basis of a rotatingdirection of the rotational axis.

An inner diameter of the side plate of the second cover may be greaterthan an outer diameter of the magnet seating member.

The second cover may include a hole through which the stator passes.

The second cover may include a third coupling part, and the first covermay include a fourth coupling part coupled to the third coupling part.

The third coupling part may be an engaging flange configured to protrudefrom the side plate and including an engaging hole, and the fourthcoupling part may be an engaging protrusion configured to protrude fromthe first cover and inserted into the engaging hole.

Another aspect of the present invention provides a steering deviceincluding a steering shaft and a torque index sensor coupled to thesteering shaft, wherein the torque index sensor includes a rotor havingan outer circumferential surface on which a first magnet is disposed, astator disposed at the outside of the rotor, a circuit board, a firstcover configured to accommodate the circuit board, a first Hall sensorand a second Hall sensor mounted on the circuit board, a magnet seatingmember coupled to the stator, a second magnet coupled to the magnetseating member, and a second cover made of a metal material and coupledto the first cover, wherein the magnet seating member and the secondmagnet are disposed between the first cover and the second cover, thesecond cover includes an upper plate in which a through hole is formedand a side plate configured to extend in a rotational axis directionfrom the upper plate, and the side plate includes a groove formed at alocation corresponding to the second Hall sensor.

Still another aspect of the present invention provides a torque indexsensor including a rotor having an outer circumferential surface onwhich a first magnet is disposed, a stator disposed at the outside ofthe rotor, a cover including a hole through which the stator passes, acircuit board disposed at one side of the cover, a first Hall sensor anda second Hall sensor mounted on the circuit board, a second magnet and amagnet shield disposed at the other side of the cover, wherein thestator includes a holder coupled to a rotational axis, the magnet shieldis coupled to the holder, the magnet shield includes an upper plate anda side plate configured to extend from the upper plate, an innerdiameter of the upper plate is the same as an outer diameter of theholder, an outer diameter of the upper plate is greater than a distancefrom a center of the holder to the second magnet and less than adistance from the center of the holder to the second Hall sensor, andthe side plate has a groove formed in a size corresponding to a width ofthe second Hall sensor.

The first Hall sensor may sense magnetic flux of the stator, and thesecond Hall sensor may sense magnetic flux of the second magnet.

The second Hall sensor and the second magnet may be disposed to face theside plate.

The second Hall sensor and the second magnet may be disposed to bealigned on the basis of a circumferential direction of the magnetshield.

The first Hall sensor and the second magnet may be disposed to face eachother.

The second magnet may include a first pole and a second pole, the firstpole may be disposed relatively inward from the second magnet, and thesecond pole may be disposed outward from the second magnet on the basisof a radial direction of the magnet shield.

The second pole may be an N-pole.

The side plate of the magnet shield may include an outer side plateconfigured to extend from an outer circumferential surface of the upperplate and an inner side plate configured to extend from an innercircumferential surface of the upper plate.

A thickness of the outer side plate may be less than a spacing distancebetween the second Hall sensor and the second magnet.

The magnet shield may be press-fitted into the holder.

The magnet shield may be formed of a ferromagnetic material.

On the basis of a radial direction of the magnet shield, the secondmagnet may be disposed in the side plate and the second Hall sensor maybe disposed at the outside of the side plate.

The torque index sensor may include a first cover including a first holethrough which the rotor passes and a second cover including a secondhole through which the stator passes.

The second cover may include a Hall sensor housing configured toprotrude from an outer surface thereof and in which the second Hallsensor is located.

The second cover may include a magnet housing configured to protrudefrom an outer surface thereof to fix the second magnet.

Yet another aspect of the present invention provides a steering deviceincluding a steering shaft and a torque index sensor coupled to thesteering shaft, wherein the torque index sensor includes a rotor havingan outer circumferential surface on which a first magnet is disposed, astator disposed at the outside of the rotor, a cover including a holethrough which the stator passes, a circuit board disposed at one side ofthe cover, a first Hall sensor and a second Hall sensor mounted on thecircuit board, and a second magnet and a magnet shield disposed at theother side of the cover, wherein the stator includes a holder coupled toa rotational axis, the magnet shield is coupled to the holder, themagnet shield includes an upper plate and a side plate configured toextend from the upper plate, an inner diameter of the upper plate is thesame as an outer diameter of the holder, an outer diameter of the upperplate is greater than a distance from a center of the holder to thesecond magnet and less than a distance from the center of the holder tothe second Hall sensor, and the side plate has a groove formed in a sizecorresponding to a width of the second Hall sensor.

Advantageous Effects

According to an embodiment, a magnetic field interference can beprevented by using a metal cover, thereby providing a favorable effectof reducing an overall thickness of a torque index sensor.

According to the embodiment, since a magnet seating member and a statorare coupled to each other in a direction perpendicular to an axialdirection of a rotational axis, the thickness of the torque index sensorcan be decreased further.

According to the embodiment, since signals are detected by fixing asecond magnet and rotating a magnet shield, the magnetic fieldinterference can be prevented and the overall thickness of the torqueindex sensor can be decreased.

According to the embodiment, since a magnet shield is directlypress-fitted into a holder and fixed to the holder, the magnet shieldcan be used as a cover without installing a separate cover.

DESCRIPTION OF DRAWINGS

FIG. 1 is a view illustrating a torque index sensor according to anembodiment.

FIG. 2 is an exploded view of the torque index sensor shown in FIG. 1.

FIG. 3 is a side view of a circuit board shown in FIG. 2.

FIG. 4 is a side view of a magnet seating member shown in FIG. 2.

FIG. 5 is a view illustrating a 1-2 cover in FIG. 2.

FIG. 6 is a view illustrating a Hall sensor housing of the 1-2 cover.

FIG. 7 is a bottom view of the 1-2 cover.

FIG. 8 is a view illustrating a magnet seating member.

FIG. 9 is a view illustrating a coupling state between a molding memberof a stator and the magnet seating member.

FIG. 10 is a view illustrating a second cover.

FIG. 11 is a view illustrating the magnet seating member included in thesecond cover.

FIG. 12 is a view illustrating a side plate disposed between a secondmagnet and a second Hall sensor.

FIG. 13 is a graph illustrating flux due to the second cover.

FIG. 14 is a table in which torque output variation amounts arecompared.

FIG. 15 is a graph illustrating the torque output variation amounts.

FIG. 16 is a view illustrating a torque index sensor according to asecond embodiment.

FIG. 17 is an exploded view of the torque index sensor shown in FIG. 16.

FIG. 18 is a side view of a circuit board shown in FIG. 17.

FIG. 19 is a view illustrating a magnet shield shown in FIG. 17.

FIG. 20 is a view illustrating a location of each of the magnet shieldand a second cover.

FIG. 21 is a view illustrating a bottom surface of the magnet shield.

FIG. 22 is a view illustrating a second magnet and a second Hall sensoron the basis of the second cover.

FIG. 23 is a view illustrating the second magnet and the second Hallsensor disposed to face each other.

FIG. 24 is a view illustrating a location of each of a rotating magnetshield and a groove.

FIG. 25 is a view illustrating an output of the second Hall sensor.

MODES OF THE INVENTION

Hereinafter, embodiments of the present invention will be described indetail with reference to the accompanying drawings. Purposes, particularadvantages, and new characteristic of the present invention may becomemore apparent from the following detailed description related to theaccompanying drawings and the embodiment. Further, terms and words usedin the specification and the claims should not interpreted with anordinary or dictionary definition and should be interpreted with ameaning and concept which coincide with a technical spirit of thepresent invention on the basis of a principle in which an inventor mayappropriately define the concepts of the terms to describe the inventionthereof in an optimal method. In addition, while describing the presentinvention, a detailed description for a related technology which mayunnecessarily obscure the spirit of the present invention will beomitted.

Further, it should be understood that, although the terms “second,”“first,” and the like may be used herein to describe various elements,the elements are not limited by the terms. The terms are only used todistinguish one element from another. For example, a first element couldbe termed a second element, and similarly, a second element could betermed a first element without departing from the scope of the presentinvention. The term “and/or” includes combinations of one or all of aplurality of associated listed items.

FIG. 1 is a view illustrating a torque index sensor according to a firstembodiment, and FIG. 2 is an exploded view of the torque index sensorshown in FIG. 1.

Referring to FIGS. 1 and 2, a torque index sensor 10 may include a rotor100, a stator 200, a circuit board 300, a first cover 400, a first Hallsensor 500, a second Hall sensor 600, a magnet seating member 700, asecond magnet 800, and a second cover 900.

The rotor 100 is disposed in the stator 200. The rotor 100 is connectedto an input shaft of a steering shaft. Here, the input shaft may be asteering shaft connected to a handle of a vehicle. The rotor 100 mayinclude a cylindrical-shaped yoke 110 and a first magnet 120 disposed onthe yoke 110. The input shaft is inserted into the yoke 110. Further,the first magnet 120 may be disposed at the outside of the yoke 110. Thefirst magnet 120 may be fixed to an outer circumferential surface of theyoke 110 by adhesion or press-fitting.

The stator 200 is disposed at the outside of the rotor 100. The stator200 may include stator rings 210, a molding member 220, and a holder230. A pair of stator rings 210 may be disposed to be spaced apart fromand opposite to each other. Further, two stator rings 210 may be fixedto an upper side and a lower side of the molding member 220,respectively. The holder 230 is coupled to the molding member 220. Theholder 230 may be connected to an output shaft of the steering shaft.Here, the output shaft may be a steering shaft connected to a powertransmission structure of the wheel side. Accordingly, the stator 200 isconnected to the output shaft and rotates together with the outputshaft.

Meanwhile, the stator 200 may be disposed adjacent to the stator rings210 and provided with a collector configured to collect a magnetizationamount of the stator 200.

FIG. 3 is a side view of a circuit board shown in FIG. 2.

As shown in FIGS. 2 and 3, the first Hall sensor 500 and the second Hallsensor 600 are disposed on the circuit board 300.

The first cover 400 may include a 1-1 cover 410 and a 1-2 cover 420. The1-1 cover 410 and the 1-2 cover 420 may be disposed to face each otherand each have a space to accommodate the stator 200 therein. The circuitboard 300 is disposed between the 1-1 cover 410 and the 1-2 cover 420.The 1-1 cover 410 may include a first hole 411 through which the rotor100 passes. Further, the 1-2 cover 420 may include a second hole 421through which the stator 200 passes.

Referring to FIG. 3, the circuit board 300 may include a first surface310 facing the 1-1 cover 410 and a second surface 320 facing the 1-2cover 420. The first Hall sensor 500 may be disposed on the firstsurface 310. The second Hall sensor 600 may be disposed on the secondsurface 320.

The first Hall sensor 500 detects the magnetization amount of the stator200 generated by an electric interaction between the first magnet 120 ofthe rotor 100 and the stator 200. The first Hall sensor 500 may bedisposed on the circuit board 300. Specifically, the first Hall sensor500 is disposed between two collectors to detect the magnetizationamount magnetized by an interaction between the stator rings 210 and thefirst magnet 120.

The rotor 100, the stator 200, and the first Hall sensor 500 areconfigurations for measuring torque. Torsion occurs in a torsion barbetween the input shaft and the output shaft due to a difference in therotation amount between the input shaft and the output shaft. When thetorsion occurs, a rotation amount of the first magnet 120 of the rotor100 becomes different from a rotation amount of the stator 200.Accordingly, since a facing surface of the first magnet 120 becomesdifferent from facing surfaces of the stator rings 210, themagnetization amount varies. The first Hall sensor 500 may detectvariation of the magnetization amount to measure torque loaded to thesteering shaft.

The second Hall sensor 600 may output a detection signal with a periodof 360° to calculate angle acceleration of the output shaft every timethe second Hall sensor 600 is adjacent to the second magnet 800 disposedon the magnet seating member 700.

The magnet seating member 700 is provided with a ring-shaped hole 710through which the stator 200 passes.

FIG. 4 is a side view of the magnet seating member shown in FIG. 2.

Referring to FIG. 4, on the basis of an axial direction C of arotational axis, the magnet seating member 700 may include a firstsurface 711 facing the first cover 400 and a second surface 721 facingthe second cover 900. The second magnet 800 may be disposed on thesecond surface 721 to face the second cover 900. The magnet seatingmember 700 may be coupled to the holder 230 of the stator 200 to rotatetogether with the output shaft when the output shaft rotates.

The second magnet 800 is disposed on the magnet seating member 700. Thesecond magnet 800 may be insertion-molded or adhesively fixed to themagnet seating member 700. The second magnet 800 rotates together withthe magnet seating member 700 when the output shaft rotates.Accordingly, as the output shaft rotates, the second magnet 800 repeatsa state of approaching and moving away from the second Hall sensor 600.

The second cover 900 covers the magnet seating member 700. The secondcover 900 is coupled to the first cover 400. The second cover 900 ismade of a metal material to guide flux generated from the second magnet800 to the second cover 900. Since a flow of the flux generated from thesecond magnet 800 to the first magnet 120 is limited by the second cover900, a separate shielding plate is not necessary to be installed toprevent a magnetic field interference in the torque index sensoraccording to the embodiment.

FIG. 5 is a view illustrating the 1-2 cover in FIG. 2, FIG. 6 is a viewillustrating a Hall sensor housing of the 1-2 cover, and FIG. 7 is abottom view of the 1-2 cover.

Referring to FIGS. 5 and 6, the 1-2 cover 420 may include a Hall sensorhousing 422 and an accommodation part 423.

The Hall sensor housing 422 protrudes from an outer surface of the 1-2cover 420. The Hall sensor housing 422 is disposed adjacent to theaccommodation part 423. The second Hall sensor 600 is located in theHall sensor housing 422. The Hall sensor housing 422 serves to fix alocation of the second Hall sensor 600. The Hall sensor housing 422 isprovided with a slot 422 a configured to accommodate the second Hallsensor 600 therein and has an open surface which is open toward theaccommodation part 423. Further, a stopper 422 b configured to restrictthe second Hall sensor 600 to prevent separation of the second Hallsensor 600 through the open surface may protrude from an inlet of theopen surface of the Hall sensor housing 422. As shown in FIG. 7, thesecond Hall sensor 600 may be disposed in the slot 422 a through aninlet 422 c disposed in a bottom surface of the 1-2 cover 420.

The accommodation part 423 may be disposed near the second hole 421 in aconcave shape from the outer surface of the 1-2 cover 420. Theaccommodation part 423 is a place where the magnet seating member 700 isaccommodated.

Meanwhile, the 1-2 cover 420 may include a fourth coupling part 424. Thefourth coupling part 424 is coupled to the second cover 900. A pluralityof fourth coupling parts 424 may be disposed along an edge of theaccommodation part 423. The fourth coupling parts 424 may be engagingprotrusions. Further, the 1-2 cover 420 may be provided with an engagingpart 425 on an edge thereof to be coupled to the 1-1 cover 410.

FIG. 8 is a view illustrating the magnet seating member, and FIG. 9 is aview illustrating a coupling state between the molding member of thestator and the magnet seating member.

Referring to FIGS. 8 and 9, the magnet seating member 700 may include afirst coupling part 720 configured to protrude from an innercircumferential surface thereof. When the magnet seating member 700 iscoupled to the molding member 220 of the stator 200, the first couplingpart 720 may be coupled to the molding member 220 in the directionperpendicular to the axial direction of the rotational axis. In thiscase, a second coupling part 221 coupled to the first coupling part 720may be disposed on an outer circumferential surface of the moldingmember 220. The first coupling part 720 may be a plurality of protrudingprotrusions and the second coupling part 221 may be a plurality ofgrooves into which the first coupling parts 720 are inserted.

When the magnet seating member 700 is coupled to the molding member 220of the stator 200, since the first coupling part 720 and the secondcoupling part 221 are coupled to each other in the directionperpendicular to the axial direction of the rotational axis, an overallthickness of the torque index sensor may be decreased. In other words,when the first coupling part 720 and the second coupling part 221 arecoupled to each other in the axial direction of the rotational axis, acoupling space in the rotational axis direction is necessary and thecoupling space causes an increase of the overall thickness of the torqueindex sensor. However, since the magnet seating member 700 of the torqueindex sensor according to the embodiment and the molding member 220 ofthe stator 200 are coupled to each other in the direction perpendicularto the axial direction of the rotational axis, the coupling spacedisposed in the rotational axis direction may be excluded.

FIG. 10 is a view illustrating the second cover, and FIG. 11 is a viewillustrating the magnet seating member included in the second cover.

Referring to FIGS. 10 and 11, the second cover 900 may include an upperplate 910 and a side plate 920. The upper plate 910 has a disk shape,and a through hole 911 through which the holder 230 of the stator 200passes is disposed in a center of the upper plate 910. The side plate920 is disposed along an edge of the upper plate 910 and is bentdownward from the upper plate 910. When the second cover 900 is coupledto the first cover 400, the side plate 920 has a shape bent andconfigured to extend from the upper plate 910 in the rotational axisdirection. As shown in FIG. 10, an inner diameter R1 of the side plate920 may be designed to be at least greater than an outer diameter R2 ofthe magnet seating member 700. Accordingly, the side plate 920 may bedisposed between the magnet seating member 700 and the Hall sensorhousing 422 on the basis of the direction perpendicular to therotational axis direction.

Meanwhile, a third coupling part 922 may be disposed on an edge of theside plate 920. The third coupling part 922 is coupled to the fourthcoupling part 424 of the 1-2 cover 420 to couple the second cover 900and the first cover 400. The third coupling part 922 may be an engagingflange configured to protrude from the side plate 920 and including anengaging hole. A plurality of third coupling parts 922 may be disposed.Further, some of the plurality of third coupling parts 922 may bedisposed adjacent to a groove 921.

FIG. 12 is a view illustrating the side plate disposed between thesecond magnet and the second Hall sensor.

Referring to FIGS. 2 and 12, the side plate 920 may be disposed betweenthe magnet seating member 700 and the Hall sensor housing 422.Accordingly, the side plate 920 covers a side surface of the secondmagnet 800 disposed on the magnet seating member 700. Further, the sideplate 920 may include the groove 921. The groove 921 is formed by anincision of a part of the side plate 920 and is a structure in which theinside and the outside of the side plate 920 communicate with eachother. The groove 921 is aligned with the second Hall sensor 600.Specifically, when the second cover 900 is coupled to the first cover400, the groove 921 is aligned with the Hall sensor housing 112 in arotating direction of the rotational axis. That is, the side plate 920covers the side surface of the second magnet 800 to cover a spacebetween the second magnet 800 and the second Hall sensor 600 so that thesecond magnet 800 and the second Hall sensor 600 face each other throughthe groove 921.

When the output shaft rotates, the second magnet 800 also rotates. Asthe second magnet 800 rotates, the second magnet 800 periodicallyapproaches or moves away from the second Hall sensor 600. Accordingly,the second Hall sensor 600 may generate a detection signal with a periodof 360°.

FIG. 13 is a graph illustrating flux due to the second cover.

Referring to FIG. 13, in a state in which a shielding structure does notexist between the first magnet 120 and the second magnet 800, it can beconfirmed that the flux generated by rotation of the second magnet 800is guided through the second cover 900.

FIG. 14 is a table in which torque output variation amounts arecompared, and FIG. 15 is a graph illustrating the torque outputvariation amounts.

In FIGS. 14 and 15, A is a torque index sensor in which a shieldingplate is installed, B is a torque index sensor without a shieldingplate, and C is the torque index sensor according to the embodiment inwhich the second cover 900 made of a metal material is installed.

As shown in FIGS. 14 and 15, in the case of the torque index sensor Bwithout the shielding plate, the torque output variation amount in asection in which an angle ranges from 40° to 160° is greatly reducedbecause a magnetic field interference occurs.

However, in the case of C in which the second cover 900 made of a metalmaterial is installed, it can be confirmed that the torque outputvariation amount is detected like the case of A in which the shieldingplate is installed. Accordingly, in the case of the torque index sensoraccording to the embodiment, it can be confirmed that the magnetic fieldinterference is effectively shielded even without installing a separateshielding plate.

FIG. 16 is a view illustrating a torque index sensor according to asecond embodiment, FIG. 17 is an exploded view of the torque indexsensor shown in FIG. 16, and FIG. 18 is a side view of a circuit boardshown in FIG. 17.

Referring to FIGS. 16 to 18, a torque index sensor 20 may include arotor 1000, a stator 1200, a cover 1300, a circuit board 1400, a firstHall sensor 1500, a second Hall sensor 1600, a second magnet 1700, amagnet shield 1800, and a holder 1230.

The rotor 1000 is disposed in the stator 1200. The rotor 1000 isconnected to an input shaft of a steering shaft. Here, the input shaftmay be a steering shaft connected to a handle of a vehicle. The rotor100 may include a cylindrical-shaped yoke 1110 and a first magnet 1120disposed on the yoke 1110. The input shaft is inserted into the yoke1110. Further, the first magnet 1120 may be disposed at the outside ofthe yoke 1110. The first magnet 1120 may be fixed to the outercircumferential surface of the yoke 1110 by adhesion or press-fitting.

The stator 1200 is disposed at the outside of the rotor 1000. The stator1200 may include stator rings 1210, a molding member 1220, and theholder 1230. A pair of stator rings 1210 may be disposed to be spacedapart from and opposite to each other. Further, two stator rings 1210may be fixed to an upper side and a lower side of the molding member1220, respectively. The holder 1230 is coupled to the molding member1220. The holder 1230 may be connected to an output shaft of thesteering shaft. Here, the output shaft may be a steering shaft connectedto a power transmission structure of the wheel side. Accordingly, thestator 1200 is connected to the output shaft and rotates together withthe output shaft.

Meanwhile, the stator 1200 may be disposed adjacent to the stator rings1210 and provided with a collector configured to collect a magnetizationamount of the stator 1200

The cover 1300 may include a first cover 1310 and a second cover 1320.The first cover 1310 and the second cover 1320 may be disposed oppositeto each other and each have a space to accommodate the stator 1200therein. The circuit board 1400 is disposed between the first cover 1310and the second cover 1320. The first cover 1310 may include a first hole1311 through which the rotor 1000 passes. Further, the second cover 1320may include a second hole 1321 through which the stator 1200 passes.

As shown in FIGS. 17 and 18, the first Hall sensor 1500 and the secondHall sensor 1600 are disposed on the circuit board 1400.

The circuit board 1400 may include a first surface 1410 facing the firstcover 1310 and a second surface 1420 facing the second cover 1320. Thefirst Hall sensor 1500 may be disposed on the first surface 1410. Thesecond Hall sensor 1600 may be disposed on the second surface 1420.

The first Hall sensor 1500 detects the magnetization amount of thestator 1200 generated by an electric interaction between the firstmagnet 1120 of the rotor 1000 and the stator 1200. Specifically, thefirst Hall sensor 1500 is disposed between two collectors to detect themagnetization amount magnetized by an interaction between the statorrings 1210 and the first magnet 1120.

The rotor 1000, the stator 1200, and the first Hall sensor 1500 areconfigurations for measuring torque. Torsion occurs in a torsion barbetween the input shaft and the output shaft due to a difference in therotation amount between the input shaft and the output shaft. When thetorsion occurs, a rotation amount of the first magnet 1120 of the rotor1000 becomes different from a rotation amount of the stator 1200.Accordingly, since a facing surface of the first magnet 1120 becomesdifferent from facing surfaces of the stator rings 1210, themagnetization amount varies. The first Hall sensor 1500 may detectvariation of the magnetization amount to measure torque loaded to thesteering shaft.

The second Hall sensor 1600 may output a detection signal with a periodof 360° to calculate angle acceleration of the output shaft when agroove 1830 of the magnet shield 1800 and the second magnet 1700 arealigned.

The magnet shield 1800 is provided with a ring-shaped hole 1811 throughwhich the stator 1200 passes.

FIG. 19 is a view illustrating the magnet shield shown in FIG. 17, andFIG. 20 is a view illustrating a location of each of the magnet shieldand the second cover.

Referring to FIG. 19, the magnet shield 1800 may include an upper plate1810 and a side plate 1820. The upper plate 1810 has a disk shape, and ahole 1811 through which the holder 1230 of the stator 1200 passes isdisposed in a center of the upper plate 1810. The side plate 1820 isdisposed along an edge of the upper plate 1810.

The side plate 1820 may include an outer side plate 1821 and an innerside plate 1822. The side plate 1821 is bent downward from an outercircumferential surface of the upper plate 1810. When the second cover1320 is coupled to the first cover 1310, the outer side plate 1821 has ashape bent and configured to extend from the outer circumferentialsurface of the upper plate 1810 in an axial direction. The inner sideplate 1822 is bent downward from an inner circumferential surface of theupper plate 1810.

The magnet shield 1800 is directly coupled to the holder 1230 of thestator 1200. Specifically, the holder 1230 of the stator 1200 ispress-fitted into the hole 1811 of the upper plate 1810 to be coupled tothe magnet shield 1800. In this case, the inner side plate 1822 guidesso that the holder 1230 may be easily press-fitted into the hole 1811 ofthe upper plate 1810. Since the magnet shield 1800 and the holder 1230are directly coupled to each other, when the holder 1230 rotates, themagnet shield 1800 immediately rotates. The outer side plate 1821includes the groove 1830. The groove 1830 allows the inside and theoutside of the outer side plate 1821 to communicate with each other.

Meanwhile, the magnet shield 1800 may be formed of a ferromagneticmaterial.

Referring to FIG. 20, the second cover 1320 may include a Hall sensorhousing 1322 and a magnet housing 1323. The Hall sensor housing 1322protrudes from an outer surface of the second cover 1320 and has a spacein which the second Hall sensor 1600 is located. A front surface of theHall sensor housing 1322, that is, a surface facing the second magnet1700, may be open. The magnet housing 1323 protrudes from the outersurface of the second cover 1320 and includes the second magnet 1700therein. The magnet housing 1323 may fix the second magnet 1700 so thata part of the second magnet 1700 may be exposed. The second magnet 1700is fixed to the second cover 1320 through the magnet housing 1323 anddoes not move. The Hall sensor housing 1322 and the magnet housing 1323are disposed to face each other.

FIG. 21 is a view illustrating a bottom surface of the magnet shield,and FIG. 22 is a view illustrating a second magnet and a second hallsensor on the basis of the second cove.

As shown in FIG. 21, an inner diameter R1 of the upper plate 1810 of themagnet shield 1800 may be the same as an outer diameter R2 of the holder1230. The magnet shield 1800 is press-fitted into the holder 1230.Further, an outer diameter R3 of the upper plate 1810 may be greaterthan a distance L1 from a center C of the holder 1230 to the secondmagnet 1700 and less than a distance L2 from the center C of the holder1230 to the second Hall sensor 1600. Accordingly, the side plate 1820may be located between the second Hall sensor 1600 and the second magnet1700 on the basis of a radial direction of the magnet shield 1800.

Meanwhile, a thickness of the outer side plate 1821 (t in FIG. 21) isformed to be less than a distance (d in FIG. 22) by which the secondHall sensor 1600 and the second magnet 1700 are spaced apart from eachother. Accordingly, the outer side plate 1821 may pass between thesecond Hall sensor 1600 and the second magnet 1700 while the magnetshield 1800 rotates.

FIG. 23 is a view illustrating the second magnet and the second Hallsensor disposed to face each other.

Referring to FIGS. 22 and 23, the second Hall sensor 1600 and the secondmagnet 1700 are disposed to face each other. That is, the second Hallsensor 1600 and the second magnet 1700 may be disposed to be aligned onthe basis of a circumferential direction of the magnet shield 1800. Inthis case, the second Hall sensor 1600 is disposed to face the outsideof the outer side plate 1821 and the second magnet 1700 is disposed toface the inside of the outer side plate 1821. Accordingly, the outerside plate 1821 is disposed between the second Hall sensor 1600 and thesecond magnet 1700. Further, the groove 1830 disposed in the outer sideplate 1821 is disposed between the second Hall sensor 1600 and thesecond magnet 1700. A width W of the second Hall sensor 1600 maycorrespond to a size of the groove 1830.

Meanwhile, the second magnet 1700 may include a first pole 1710 and asecond pole 1720. The first pole 1710 may be an N-pole and the secondpole 1720 may be an S-pole. The first pole 1710 may be relativelydisposed outward from the second magnet 1700 and the second pole 1720may be relatively disposed inward from the second magnet 1700. The firstpole 1710 is disposed to face the second Hall sensor 1600.

The magnet shield 1800 rotates together as the holder (1230 in FIG. 17)rotates. In this case, the second magnet 1700 is in a fixed state.Accordingly, flux of the second magnet 1700 which causes a magneticfield interference at the first magnet 1120 and the first Hall sensor1500 is not generated. Thus, a separate shielding plate configured toshield a magnetic field does not have to be installed. When a shieldingplate is installed, an overall thickness of the torque index sensor isincreased due to an installing space of the shielding plate, and since ashielding, plate does not have to be installed in the torque indexsensor according to the embodiment, there is an advantage that theoverall thickness of the torque index sensor can be decreased.

FIG. 24 is a view illustrating a location of each of the rotating magnetshield and the groove and FIG. 25 is a view illustrating an output ofthe second Hall sensor.

FIG. 24A shows a state in which the outer side plate 1821 blocks thesecond Hall sensor 1600 and the second magnet 1700. In the state in FIG.24A, as shown in FIG. 25, since an output is not generated from thesecond Hall sensor 1600, a signal is maintained in an off state. Afterthat, when the magnet shield 1800 rotates in a clockwise direction CW,the groove 1830 disposed on the outer side plate 1821 also rotates inthe clockwise direction CW. In the state in FIG. 24B, when the groove1830 becomes close to the second Hall sensor 1600, the second magnet1700 and the second Hall sensor 1600 communicate with each other, andaccordingly, the output of the second Hall sensor 1600 is generated andthe signal is converted to an on state. In addition, in states in FIGS.24C and 24D, the output of the second Hall sensor 1600 is generated andthe signal is maintained in an on state as rotation of the magnet shield1800 continues and thus until the groove 1830 passes through the secondHall sensor 1600, that is, until the outer side plate 1821 completelycovers the second Hall sensor 1600 and the second magnet 1700. Inaddition, when the rotation of the magnet shield 1800 is maintained andthus the outer side plate 1821 completely covers the second Hall sensor1600 and the second magnet 1700, in the state in FIG. 24E, the output ofthe second Hall sensor 1600 is not generated and the signal is convertedto an off state.

As described above, although an example in which the magnet shield 1800rotates in the clockwise direction CW is described, even when the magnetshield 1800 rotates in a counterclockwise direction CCW, turning on oroff of the signal corresponding to the output of the second Hall sensor1600 may be converted according to a location of the groove 1830 of theouter side plate 1821.

As described above, the torque index sensor 20 according to theembodiment may generate an on or off signal according to a period inwhich the location of the groove 1830 disposed in the side plate 1820 ofthe magnet shield 1800 and the locations of the second Hall sensor 1600and the second magnet 1700 are aligned in a state in which the secondmagnet 1700 does not rotate and is fixed. Accordingly, the flux may begenerated by rotation of the second magnet 1700 and the magnetic fieldinterference caused by the flux may be prevented.

The torque index sensor according to one embodiment of the presentinvention and the steering device including the same have been describedin detail with reference to the accompanying drawings in the above.

The embodiment of the present invention should be considered to beexemplary and not limited, and the scope of the present invention willbe shown by the appended claims rather than the above-described detaileddescription. Further, all changeable or modifiable shapes derived frommeanings and scope of the claims and equivalents of the above should beconsidered to be within the scope of the present invention.

The invention claimed is:
 1. A torque index sensor comprising: a rotorhaving an outer circumferential surface on which a first magnet isdisposed; a stator disposed at the outside of the rotor; a circuitboard; a first cover configured to accommodate the circuit board; afirst Hall sensor and a second Hall sensor mounted on the circuit board;a magnet seating member coupled to the stator; a second magnet coupledto the magnet seating member; and a second cover made of a metalmaterial and coupled to the first cover, wherein the magnet seatingmember and the second magnet are disposed between the first cover andthe second cover, the second cover includes an upper plate in which athrough hole is formed and a side plate configured to extend in arotational axis direction from the upper plate, and the side plateincludes a groove formed at a location corresponding to the second Hallsensor.
 2. The torque index sensor of claim 1, wherein the first coverincludes a Hall sensor housing configured to protrude from an outersurface of the first cover and in which the second Hall sensor islocated.
 3. The torque index sensor of claim 2, wherein: the Hall sensorhousing is provided with a slot configured to accommodate the secondHall sensor; and the slot has an open surface.
 4. The torque indexsensor of claim 3, wherein the slot includes a stopper configured toprotrude from an inlet of the open surface.
 5. A steering devicecomprising: a steering shaft; and a torque index sensor coupled to thesteering shaft, wherein the torque index sensor includes a rotor havingan outer circumferential surface on which a first magnet is disposed, astator disposed at an outside of the rotor, a circuit board, a firstcover configured to accommodate the circuit board, a first Hall sensorand a second Hall sensor mounted on the circuit board, a magnet seatingmember coupled to the stator, a second magnet coupled to the magnetseating member, and a second cover made of a metal material and coupledto the first cover, wherein the magnet seating member and the secondmagnet are disposed between the first cover and the second cover, thesecond cover includes an upper plate in which a through hole is formedand a side plate configured to extend in a rotational axis directionfrom the upper plate, and the side plate includes a groove formed at alocation corresponding to the second Hall sensor.
 6. A torque indexsensor comprising: a rotor having an outer circumferential surface onwhich a first magnet is disposed; a stator disposed at the outside ofthe rotor; a cover including a hole through which the stator passes; acircuit board disposed at one side of the cover; a first Hall sensor anda second Hall sensor mounted on the circuit board; and a second magnetand a magnet shield disposed at the other side of the cover, wherein thestator includes a holder coupled to a rotational axis, the magnet shieldis coupled to the holder, the magnet shield includes an upper plate anda side plate configured to extend from the upper plate, an innerdiameter of the upper plate is the same as an outer diameter of theholder, an outer diameter of the upper plate is greater than a distancefrom a center of the holder to the second magnet and less than adistance from the center of the holder to the second Hall sensor, andthe side plate has a groove formed in a size corresponding to a width ofthe second Hall sensor.
 7. The torque index sensor of claim 6, whereinthe second Hall sensor and the second magnet are disposed to face theside plate.
 8. The torque index sensor of claim 7, wherein the secondHall sensor and the second magnet are disposed to be aligned on thebasis of a circumferential direction of the magnet shield.
 9. The torqueindex sensor of claim 6, wherein: the second magnet includes a firstpole and a second pole; and the first pole is relatively disposed inwardfrom the second magnet and the second pole is relatively disposedoutward from the second magnet on the basis of a radial direction of themagnet shield.
 10. A steering device comprising: a steering shaft; and atorque index sensor coupled to the steering shaft, wherein the torqueindex sensor includes a rotor having an outer circumferential surface onwhich a first magnet is disposed, a stator disposed at the outside ofthe rotor, a cover including a hole through which the stator passes, acircuit board disposed at one side of the cover, a first Hall sensor anda second Hall sensor mounted on the circuit board, and a second magnetand a magnet shield disposed at the other side of the cover, wherein thestator includes a holder coupled to a rotational axis, the magnet shieldis coupled to the holder, the magnet shield includes an upper plate anda side plate configured to extend from the upper plate, an innerdiameter of the upper plate is the same as an outer diameter of theholder, an outer diameter of the upper plate is greater than a distancefrom a center of the holder to the second magnet and less than adistance from the center of the holder to the second Hall sensor, andthe side plate has a groove formed in a size corresponding to a width ofthe second Hall sensor.